As wireless communication techniques have been developed, wireless communication terminals including cellular phones have been widely available to the general public. Further, as performances of the wireless communication terminals have been developed, various services including communication services such as voice communication or data communication and application services thereof are provided. In particular, an emergency rescue service has been provided by using attributes of the wireless communication terminals such as portability and a possibility of being tracked.
An emergency rescue request using the wireless communication terminal has been available by the following two methods. A first method is to directly send location information to a location information server by using a GPS module installed in a wireless communication terminal. A second method is that a wireless communication terminal transmits location information of base stations to a location information server in the form of phase information) and the location information server then checks location information of the wireless communication terminal by a triangulation method.
In case of using the first method, if the GPS module is not installed in the wireless communication terminal or the wireless communication terminal is located in a closed space where a GPS signal can not reach, it is difficult to perform location tracking.
In case of using the second method, a signal delay or a change in call strength may be incurred due to a repeater positioned between the wireless communication terminal and the base station, so that an error may occur in checking the location information.